*Breaking change* The `tor` configuration field is no longer
supported. Users must remove that field from their config.
Allows for a mixed mode, where regular addresses bypass the Tor proxy,
while onion addresses go through it.
When `onion.mode` is set to "forward", Tor connections are fowarded to
the global proxy, and if it isn't set, to the OS's DNS resolution.
For mixed mode, a global proxy simply isn't set, so that IP/DNS is not
proxied.
ca7db1620c